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Lecture

Topological defects in layered 2D crystals:Structure, properties and their applications



Point-like or extended defects in layered crystals, predominantly in graphene, have widely been studied and their impacts on properties are manifold. Like in established semiconductor technologies, crystal defects yield novel functionalities, e.g., for optoelectronics and sensors.

For instance, dense dislocation networks, introducing extraordinary structural and electronic disorder, yield a perfectly linear magnetoresistance of bilayer graphene well suited for magnetic field sensing up to 100T [1]. In layered semiconductors, similar defects may cause strong band-structure alterations with a highly localized optical response.

For advanced applications in optical communication, imaging, or light-harvesting, multispectral devices with extended photosensitivity from the visible towards the IR range are desired. Defective few-layer MoS2[2]. with broad IR-sensitivity has successfully been introduced into the established fabrication sequence of vertical photodetectors based on amorphous Si [2]. Bias-dependent charge utilization within the devices even allows for wavelength-selective sensing.

 

Speaker:
Charles Otieno Ogolla
University of Siegen
Additional Authors:
  • Prof. Benjamin Butz
    Universität Siegen
  • Dr. Andreas Bablich
    Universität Siegen
  • Dr. Julian Müller
    Universität Siegen
  • Prof. Dr. Peter Haring Bolivar
    Universität Siegen